Document And Entity Information	3 Months Ended
	Mar. 31, 2013	May 01, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	GUARANTY FEDERAL BANCSHARES INC
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		2,731,519
Amendment Flag	false
Entity Central Index Key	0001046203
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Smaller Reporting Company
Entity Well-known Seasoned Issuer	No
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1